Drawbench for metal tubing



June3,l924; 1,496,125

D. C. LARSON DRAWBENCH FOR METAL TUBING Filed Dec. 14. 1921 4 Sheets-Sheet 1 Mom/14mg June 3 19.24. 1,496,125

A D. C. LARSON DRAWBENCH FOR METAL TUBING Filed Dec. 14 1921 4 Sheets-Sheet 2 avwe/wboz 52 [m 351 Momm cf.

fig i 208 June 3 1924.

D. C. LARSON DRAWBENCH FOR METAL TUBING 4 Sheets-Sheet 3 Filed Dec. 14. 192] awve/wtoz M- 6.6% 5B1 GHQ cum WM June 3 1924.

D. c. LARSON DRAWBENCH FOR METAL TUEING Filed Dec. 14 192] 851 /4; 343 6001494 MWW 4 Sheets-Sheet 4 Patented June 3, 1924.

UNITED STATES 1,496,125 PATENT OFFICE.

DAVID C. LARSON, OF YONKERS, NEW YORK, .ASSIGNOR TO SUNDH ENGINEERING AND MACHINE COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION 0F PENNSYLVANIA.

DRAWBENCH FOR METAL TUBING.

Application filed December 14, 1921.

To all ill/(0172 it may concern Be it known that 1, DAVID C. Larson, a citizen of the United States, residing in Yonkers, in the county of \Vestchester and State of New York, have invented a new and useful Improvement in Drawbenches for Metal Tubing, of which the following is a specification.

My invention relates to draw benches or drawing machines for drawing metal blanks, such as tubes orrods from ductile metal, and more particularly to an improved system of control therefor, having application to an electrically operated machine, being illustrated in conjunction with same.

.A feature of the invention resides in the provision of means for obtaining variable speeds of the draw bench, also a quick operation of same. Another feature resides in the provision of means for obtaining a simple and easy control, whereby a high (production by the draw bench can be obtained by an unskilled operator.

A further feature resides in the provision of means for obtaining an automatic return operation of the drawing mechanism, and in a combination of automatic and manual operation, the automatic operation taking the place of the manual operation, but at any time the operation can be had by the manual means.

I attain these features by the mechanism illustrated in the accompanying drawings, in 'which Figure 1 is a plan view of the entire machine.

Figure 2- is a diagram of the system of electric circuits of the machine.

Figures 3, 4 and 5 are views in elevation of sections of one of the sides of the draw bench of the machine.

Figures 6, 7 and 8 are views in elevation of sections of the other side of the draw bench of the machine.

Similar characters refer to similar parts throughout the several views.

The frame bars, 1 and 2, their legs or standards, 3-3, etc'.,' standards 4t, securing the frame bars, 1 and 2, to a bed plate 5, upon which is mounted a drum, 6, gearing 7and 8, and a brake 9, together with a tank 10, also secured to the frame bars, 1 and 2, supported by legs or-sta'ndards, 11, together Serial No. 522,249.

' with other parts to be described hereinafter,

An electric moconstitute the draw bench. tor, 12, secured to a bed plate, 13, is for operating the draw bench. Between the frame bars, 1 and 2, is a traveling draw mechanism, 14, its supporting members, 15, 16 and 17, having sliding contact upon the surface of the frame bars, 1 and 2, and moves thereon to draw a tube, not shown, over a mandrel, also not shown, through die, 18, when pulled by pulling cables, 19, and moved to return to the die to be in a position to draw a succeeding tube, when pulled by return cables, 20, the pulling and return cables winding on and off the drum, 6, as the case may be, in opposite directions to each other, when the drum is caused to be moved by rotation of the motor, 12,'through the inter-mediation of the gearing, 7 and 8.

Referring to Figure 7, therein a part of the frame bar, 1, is cut away, showing the draw clamp mechanism, and also in this view is shown th connection of one of the return cables,-20, to the mechanism, from which point the cables and also the other return cable, 20, it being secured on the opposite side ofthe mechanism, extend along through grooves, not shown, in the inner sides of the frame bars, 1 and 2, together with crosspiece, 21, to which the cables are secured, the grooves acting as a guide to the cables, and to the traveling draw clamp by means of the crosspiece, the cables extending to and over pulleys,.22, shown incased in the tank, 10. In Figure 1, a part of the pulleys extending underneath the tank as seen in Figures 3 and 6, from which the cables extend underneath the draw bench, over a pair of guide pulleys, 23, on the bed plate, 5, to the drum upon which they are wound, as already stated. The pulling cables, 19, are connected to the draw clamp by an equalizing hitch bar, 2 1, from which the cables extend to and are wound thereon, on the drum,

6, as already stated.

To the tank,'10, is secured a shelf, 25,

which is adapted'to hold a tube and man-f drel, one end of the tube tobe projected I out through the die, 18. The mechanism,

26, at the rear of the tank contains slots, 27 and 28, in which one end'of a mandrel 1s placed and held therein when the'end portion of a tube extending out through the die;

-18, is gripped by the draw clamp, '14, to

draw the tube over the mandrel and through the die.

All of which description of the draw bench is definite but thought clear and suflicient as a description ofthe same, as the draw bench in mind is on the lines of a well known type of manufacture and considered well known to those skilled in the tube drawing art.

The description will now begin to describe the parts of the improved features of' the present invention and their operation n10 011- trolling the operation of the draw bench ust described.

In beginning I will briefly describe a com bination of means for obtaining a source of power foroperating the motor, 12, of the draw bench, for which combination of means I have applied for Letters Patent of the United States, November 18, 1921, application filed November 23, 1921, Serial No.

517,219, entitled Operating systems for draw benches, and as the present invention relates also to draw benches I have illustrated the first said invention with the present one.

As illustrated in Figure 1, A represents the said combination in its entirety, and as can be seen without further description, comprising generators, B, B and Bf which are operable through the intermediation of the other parts of the combination; however,

only the generator B, of the combination, is

shown applied tothe present invention; but it is manifest that the other generators may be applied, if and when desired.

In Figures 1, and 3 to 8 inclusive, the position of the various elements is illustrated by which the objects spoken of hereinbefore in the operation and control of the draw bench are obtained. A main line switch C, and controlling mechanism,

are shown for controlling the draw bench mechanism. A floor controller, F, of a well known type is convenientlymounted' upon the bed plate, 5, and is driven from a shaft,

29, of a drawing drum, 6, through a sprocket and chain connection, 30, the floor controllerfunctioning to time the operation of several of the switches of the control.-

ling mechanism as hereinafter described. A

key button switch, D, of a known type is shown adapted to be operated by a key,-

which may be retained in possession of a 7 person other than the operator or attendant of the draw bench, such as the foreman, for example, so that the operator or attendant of the draw bench cannot change the speed of the draw bench as hereinafter described. A manual controlling switch, E, of the weight and dash-pot type is shown, for controlling the draw bench. as hereinafter described. A switch, H, for controlling the limits of travel of the drawin mechanism, 14, in either direction, is located on the outer side of the frame bar of the 33, in one direction of travel of the clamp,

mechanism, and underneath an arm, 34, of a lever 35, in the opposite direction of travel of the clamp mechanism. lVhen operating the lever, 33, its other arm, 36, will move a rod, 37, to the right of the observer, lifting a roller, 38, of the switch H out of a groove 39 in the rod, opening the switch as a result, its contacts being in the com mon circuit of the reversing switches, the contacts when open will result in either reversing switch becoming in operative, and the driving mechanism, 14, will be stopped. When operating the lever 35, its other arm, 40, will move the rod, 37 to the left of the observer, lifting the roller, 38, from out of the groove, 39, in the rod, opening the switch H, the result being as told when the lever 33 is operated. Brackets 41 secured to the frame bar, 1, are adapted to hold and guide the rod, 37.

Referring now to Figure 2, the elements will first be designated, they comprising a suitable source of current supply designated and the main line switch C, reversing switches R, R, each controlling a set of back contacts, 43, the electric actuating motor 12 for the drawing mechanism having a field winding 44, the electric generator B, having a field winding 45, a nonreversing holding magnet 46, controlling a pair of normally open contacts 47, an overload magnet 48, two windings controlling a pair of normally closed contacts 49, a nonreversing magnet 50, controlling a pair of normally closed contacts 51, a slow down magnet 52, controlling a pair of normally closed contacts 53, a generator field magnet 54, controlling a pair of normally closed contacts 55, and a pair of normally open contacts 56, additional generator field magnets 57. 58, 59 and 60, each controlling two pairs of normally open contacts 61 and 62 respectively, the key button switch D, comprising contacts 63 to 69 inclusive, floor controller switches 70 to 78 inclusive, the manually operated switch E, consisting of contacts 79 to 91 inclusive, and segment 252 together with a magnet winding 92, with which segment 93 on the lever 253 of'the switch cooperates.

The generator field magnets 54, 57, 58, 59 and 60, function as accelerating magnets. each, in o'p'erating by means of one of their pairs ofcontacts, cut out resistance in the circuit of the generator field, 45, thereby increasing the strength of the field, and as a result more current is generated by the generator, B, which current is supplied to the motor, 12, the result of the'operation of the said magnets increasing the speed of the motor. The closing of the other pair of contacts of each of the said magnets completes a circuit for each of the succeeding said magnets in their sequence of operation. The key button switch, D, is a further means of controlling the amount of current in the field winding, 45, of generator B. A key inserted in the openings in the switch, D, for that purpose, actuates a separate mechanism for each pairof contacts of which a diagrammatical illustration is made in Fi ure 2, which mechanism is adapted to brid e each of the airs of contacts of the switch?) as desired. aving thus pointed out the various elements constituting the present improved controlling system, their operation will be now described. In beginning the description of the operation, it is assumed that the generator B is operating through the means of the power combination, A, and that the main line switch C" through which another suitable source of current is obtained for operating is closed. \Ve will assume that a tube to be drawn is in place on the bench and the draw clamp mechanism 14 has been caused to grip the end portion of a tube that protrudes through the die. To operate the draw bench to draw a tube, the manually operated switch E is turned to the right of the observer. A circuit is thereby established as follows: from plus main, switch C, by wire'114, junction point 117, by wire 116, junction point 115, by wire 94,

" switch E, contacts 79 and 80, by wire 95,

floor controller switch 77,said switch having been closed by a previous return operation of the draw bench-, by wire 96, through the winding of the reversing switch R, by wire 97, junction point 98, by wire 99, junction point 100, by wire 101, contacts 49 of the overload magnet 48. Also from the junction point 100, circuit is traced by wire 102, through the lower winding of the overload magnet 48, by wire 103, adjustable resistance 104. This last circuit is for holding the contacts of the overload magnet open, when required, and the reason for the same will be told hereinafter. From the contacts 49 the circuit is further traced by wire 105, junction point 106, by wire 107, through contacts 51, of the non-reversing magnet 50, by wire 107, closed contacts 108 of the limit switch H, by wire 109, junction point 110, by wire 111, junction point 112, by wire 113, switch C, to the minus main. A circuit for the winding 44 of the motor may be traced from the plus main, switch C, by wire 114, junction point 117, by wire 118, junction point 119, from which point a parallel circuit to the motor winding is had by way of wire 120, through the bridge contacts 55, by wire 121, to the motor winding, or from the junction point 119, by wire 122, through the bridge contacts 43 of the reversing switch R,

by wire 123, to the motor winding 44,

through the winding, by wire 124, junction point 112, by wire 113, switch C to the minus main.

Both circuits of the motor winding 44, just traced parallel a resistance 215, the contact in each circuit being opened in the return operation of the draw mechanism 14 to the die 18. The reversing switch It being operated to accomplish the return operation, opening its back contacts 43, as a result of this operation, and the contacts 55, of the generator field ma net 54 opening by the operation of the said magnet throu h operation of the manual operated switci E, result in the insertionof the resistance 215, in the motor winding 44 circuit, weakening the motor field as a result, which causes the motor to operate at an additional speed above the speed obtained up to the point before operating of the generator field magnet 54. All of which operation is for a quick return of the draw mechanism 14, back to the die, 18. The above operation is not had in the pullin operation of the draw mechanism 14, though the generator field magnet 54 operates as in the return operation. The resistance 215 remains short circuited in the pulling operation, by the contacts 43 of the reversing switch R. The winding of the reversing magnet R, at this time receiving current, will close its normally open contacts completing a circuit for the winding 45 of the generator B, traced from junction point 119, by wire 125, contact 126, of the reversing switch R, b wire 127, contact 128, of reversing switch segment 129, as the magnet has closed its contacts, contact 130, of the magnet, by wire 131, contact 132 of reversing magnet R, by wire 133, junction point 134, by wire 135, junction point 136, through the resistance 137, 138, 139 and 140, considering at this time that none of the key buttons of the switch D have been operated, junction point 141, by wire 142, junction point 143, by wire 144, junction point 145, through resistances 146, 147, 148, 149 and 150, junction point 151, j

by wire 152, through the winding 45 of the generator B, by wire 153, contact 154, se ment 155, and contact 156, of the magnet by wire 157, junction point 158, by wire 159, junction point 110, by wire 111, junction point 112, wire 113, switch C, to the minus main. The generator winding 45, now taking current and also the motor winding 44, the generator will deliver current to the armature of the motor and cause it to operate, the circuit of the generated current being traced from the brush 172 of the generator, junction point 171, by wire 170, through the winding of the non-reversing holding magnet 46, by wire 169, through the top winding of the overload magnet 48, by wire 168, junction point 167, by wire 166,

through brush 165, motor and brush 164 of the motor, by wire 163, junction point 162, by wire 161, to brush 160 of the generator.

The motor, 12, of the draw bench now operating it will draw the draw clamp mechanism, 14, through the intermedi'at'ion of the pulling cables, 19, drum 6, and gearing 7, drawing a tube in place on the bench through the die 18.

The floor controller F is also operating at this time through the sprocket and chain connection 30, 'driven from the shaft 29 of the drum v6, and through the, movement of its parts first effects the closing of its switch 75, and with further movement of the switch E to the right, the two effect the establishment of a circuit, traced from plus main, switch C, by wire 114, junction point 117, by wire 116, junction point 115, by wire 94, contact 79, the segment 252 and contact 81 of the switch E, by wire 173, switch 75 of the floor controller F, by wire 174, junction joint 175, by wire 176, through the winding of generator field magnet 60, by wire 177, junction point 178, by wire 179, junction point 180, by wire 181, junction point 182, by wire 183, contact 184, segment 155, and contact 156 of the reversing switch R, as the contact closed through a previous operation, by wire 157, junction point 158, by wire 159, junction point 110, by wire 111, junction point 112, by wire 113, switch C, to the minus main. The generator field magnet 60 has been operated as a result of this last traced circuit and each succeeding magnet 59, 58, 57 and 54, is operated through the further operation of the floor controller F, efiecting to close its succeeding switches, 73 and 71, together with the further operation of switch E. For operating the remaining generator field magnet the current is obtained from the enerator B. The magnets when operated c ose their contacts, the contacts 62 of one magnet completing the circuit for the winding of the succeeding magnet and since the magnet 60 has been operated, a circuit for the operation of magnet 59 can be traced at this time, from brush 172 of the generator, junction point 171, by wire 199, junction point 117 y wire 94, junction point 115, by wire 94', contact 79, segment 252, and contact 82, as they are bridged at this time by the segment 252, by wire 198, through the switch 73, of the floor controller F, as it is closed at this time, junction point 197, by wire 199, through the winding of the generator field magnet 59, by wire 195, contacts 62 of the field magnet 60, by wire 194, junction point 193, by wire 192, junction point 191, by wire 190, junction point 192, by wire 161, to brush 160 of the generator. The field magnet 59 having been operated, its'contacts 62 are now closed, and as a consequence a circuit for the operation of means enerator field ma trom the brush 172 of the generator B, junction point 171, by wire 199, junction oint 117, by wire 116, junction point 115, By wire 94, contact 79, se ent 252, and contact 83 of switch E, by wire 204, through the contacts 69 ofthe key operated switch D, they must be closed at this time, by wire 203, through the coil of generator field magnet 58, by wire 202, contacts 62 of field magnet 59, junction point 201, by wire 200, junction point 193, to brush 160 of the generator, by 'way, of junction point 191, and wire 190, as heretofore traced, resulting in the operation of generator field magnet 58. lhe circuit for operating generator field magnet 57, is traced from contact 79 of the switch E, as up to this point the cir cuit is the same as traced for operating the preceding field magnets, contact 79, segment 252, and contact 84, of switch E, by wire 211, through the contacts 67 of the key operated switch D, also closed at this time,by wire 210, through the switch 71, of the floor controller F, as they are closed at this time, by wire 209, junction point 208, by wire 207, through the winding of generator field magnet 57, by wire 206, through the contacts 62 of the generator field magnet 58,-junction point 205, by wire 200,

and junction point 193, to the brush 160 of.

the generator B, as before. The circuit for operating generator field magnet 54, is traced from contact 79, of the switch E, segment 252 and contact 85, of the switch E, by wire 214, throigh contacts 64 of the key operated switch closed at this time, by wirev'213, through the winding of the generator field magnet 54, by wire 212, through the contacts 92 of the generator field magnet 57, by wire 200, and junction goint 193 to the brush 160 of the generator As all the generator field magnets have been operated, they, through the closing of their contacts 61, cutout of circuit with the generator winding a resistance in series therewith, the circuit through the contacts 61 of generator field magnet being traced first asthe said magnet was the first operated, the circuit being traced from the junction point 145, as up to this point the circuit is unchanged and which was traced up to and through this point heretofore, from junction point 145, through the resistances 146, 147, 148 and 149, junction point 185, by wire 186, junction point 187, by wire 188, through the contacts 61 of the field magnet 60, by wire 189, junction point 151, from whichpoint the circuit is traced, through the winding 45 of the generator and to the minus main as heretofore described. The resistance 150 has been cut .out of circuit with the generator winding 45. through the circuit just traced.

et 58 can now be traced through the contacts 61, of field magn remaining field magnets 59, 58, 57 and 54, the closing of which cuts out resistances 149, 148, 147 and 146, respectively, in the generator winding 45, as did the contacts 61 of the field magnet 60 in cutting out the resistance 150, can be traced from the junction point 145 as up to this point the circuit is the same as traced to and through this point hereintofore. Considering at this time that the contacts 61 of field magnet 59 are closed,'thc circuit is traced from jluiction point 145, through the resistance 146, by wire 216, junction point 217, by wire 218, through the resistance 147, by wire 218, junction point 219, by wire 220, through the resistance 148, by wire 221, junction point 222, by wire 223 junction point 224, by wire 225, through the contacts 61 of field magnet 59, by wire 226, junction point 187, from which point' the circuit is traced through the winding 45 of the generator and to the minus main as heretofore described. The resistance 149 has been cut out of circuit with the generator winding 45 by the last traced circuit. Considering now that the contacts 61 of field magnet 58 have closed, the circuit is traced from junction point 219, by wire 227, junction point 228, by wire 229, through the contacts 61, by wire 230, junction point 224, from which point the circuit is traced to the winding 45 as shown in the case of the closed switches 61 of field magnets 59 and 60. The resistance 148 has been cut out of circuit with the generator winding 45, by the last traced circuit. Considering that contacts 61 of field magnet 57 are now closed, the circuit is traced from junction point 217, by wire 231, junction point 232, by wire 233, et 57, by wire 234, junction point 228, from which point the circuit is traced as in the case of the preceding magnets. The resistance 147 has been cut out of circuit with the generato'r field winding 45, by the last traced circuit. Considering that contacts 56 of field magnet 54 are now closed, the circuit is traced from junction point 143, by wire 235, through the contacts 56, by wire 236, junction point 232, from which the circuit to the winding 45 is'traced as in the preceding cases.

The operation of the generator field magnets just described each cuts out of circuit with the winding 45 of the generator an operable resistance, so to speak, allowing more current to enter the winding, the generator as a result delivering more generated current to the motor, 12, speeding up the same and consequently the speed of the drawing mechanism 14. There still remains in the common circuit to the winding 45, set resistances 137, 138, 139 and 140 con trolled by the key button switch D. These resistances are to be cut in or out of circuit with the winding 45 of the genera tor, to still further the speed of the motor 12 and drawing mechanism 14, if the desired speed is not obtained by the means already described, and as told hereinbefore, it is at the will of the person in charge of the draw bench and not the operator or attendant to do so, this bein for the reason that the operator or atten ant cannot change the speed, of the motor 12 and consequently the drawin mechanism 14 after it has once been set. 11 the instance of wanting to cut out resistance 137, its circuit is traced from junction point 136, by wire 237, through the contacts 68 of the switch D, by wire 238, junction point 239, through the remaining resistances to junction point 141. When wanting to cut out resistance 138, the circuit is traced from junction point 239, by wire 238, by wire 240, through contacts 66, by wire 241, junction point 242, through the remaining resistances 139 and 140 to junction. point 141. When wanting to cut out resistance 139, the circuit is traced from junction point 242, by wire 241, by wire 243, through contacts 65, by wire 244, unction point 245, through the resistance 140,

to junction point 141. And when wantin to cut out resistance 140, the circuit is trace from junction point 245,by wire 244, by wire 246, through contacts 63, by wire 247, to junction point 141. When all the contacts of the switch are closed the circult is traced through the contacts and their ad oining wires to and through junction point 141, to the generator winding 45, as heretofore described.

So far the description has described the operation of the elements in starting the motor 12 and consequently the drawing mechanism 14 for drawing a tube, and elements for bringing the said motor and drawing mechanism up to s eed and theunits associated therewlth. T e description will now describe the other elements of control, for instance the magnet 50, which heretofore was termed a non-reversal magnet, the, operation of which prevents a su den reversal of the motor 12 and consequently the drawing mechanism in either direction of rotation and travel respectively, its contacts 51, inserting a resistance 251 in the common circuit of reversing switches R and B after either reversing switch has been operated through a circuit through the contacts 51 of the magnet 50, after the operation of which by means of current delivered by the generator B, opens its contacts inserting the resistance in the said that the mechanism must be brought to a dead stop through the operation of switch E, before an operation of the switch E in a reverse direction to operate the reversing switch R, will result in any reverse direction of motor rotation and travel of the drawing mechanism 14, the magnet 50 operating as before in the case of operation of the reversing switch R. The circuit for operating the magnet 50, is traced from brush 172 of the generator, junction'point 171, by wire 170, through the winding of mag net 46, by wire 169, through the upper winding of magnet 48, by wire. 168, unction oint 167, by wire 250, junction point 249, y wire 248, through the winding of magnet 50, by wire 248, unction point 191, by wire 190, junction point 162, by wire 161, to the brush 160 of generator B. v

Magnet 48, heretofore termed an overload magnet operates to protect the motor 12, for instance, in starting the tube to be drawn, which may not move through sticking or jambing, or at any otherpart in the actual drawing of the tube for the same reason, resultin in the motor in trying to overcome the a ove ill feature in drawing an excessive current from the generator B. The magnet 48, its upper winding being in circuit with both motor and generator as heretofore shown, responds to the excessive current, opening its contacts 49, which are in circuit with the reversing switch R, resulting in rendering the reversing switch inoperative, the contacts of which are in circuit with the winding 45 of the generator, as heretofore shown. The circuit to the winding 45 of the generator being open, the generator can no longer deliver a current to the motor for operating the same. Should the operator of the bench still hold the switch E in an operative position for operating the reversing switch, the latter will remain inoperative since, when the upper winding of switch 48 caused its contacts 49 to open, it at that time placed its lower winding and the adjustable resistance 104 in circuit with the reversin switch, the circuit through the lower winding holding the contacts 49 open. It therefore results in the operator to center his switch E, after which he may again start operation of the draw bench. Magnet 46, heretofore termed 'a nonreversing holding magnet, operates to cause automatically the start of the return operation of the drawing mechanism 14, after the completion of a drawing operation. The winding of the said magnet, 46, is in series with both the motor 12 and the generator B,

as hereinbefore shown, being directly operated by the current flowing between the same. The contacts 47 of the magnet, 46, are in circuit with the magnet 92 in switch E, the circuit is from junction point 115, by wire 256, contacts 47 they being closed at this time, by wire 257, magnet 92, by wire 258, junction point 178, by wire 179, junction point 180, by wire 181, junction point 182, by wire 183, contact 184, segment 155, contact 156, as they are closed at the time, by wire 157, junction point 158, to the minus main of switch C as before.

In a normal operation of the draw bench the operator or attendant will operate the switch E, to an extreme right position; in doing so the segment 93 fastened to the lever 253 of the switch will contact with the magnet 92. .The magnet 46 has already operated, as told before, its contacts 47 are therefore closed resulting in the energization of the winding of the magnet 92, as told hereinbefore, therefore when the lever, 253, of the switch E, has been carried to an extreme right position in which segment 93 on the lever has contacted with the core of the magnet 92, as a result the lever 253 of the switch E, will be held in this operated position by the attraction of the magnet 92 until the completion of the drawing operation; after which the current drawn by the motor from the generator to continue the travel of the draw mechanism 14 becomes less. The effect of the slump in the current, so to speak, causes the magnet 46 to open its contacts 47, which deenergizes the magnet 92, it in turn releasing its hold upon segment 93 of the lever of the switch E, which will be returned to center by a weight 254, and continue to move in a direction to the left past center. The time constant of the return movement of'the lever is controlled by a dash-pot 254. This movement will result in the segment 252 making contact with the contacts 86 to 91 inclusive of the switch which will effect an operation of the elements for a reverse operation of the motor, the drawing mechanism 14, returning automatically to the die to be in a position to draw another tube. The floor controller F operating its switches 74, 72 and respectively, and as in the drawing operation the switch E and floor controller F operating jointly, result in the operation of the generator field magnets as before, in addition to which the resistance 215 is inserted in the circuit of the winding 44 of the motor 12, to further the speed of the return of the draw mechanism 14 to the (lie 18, to be in a position to draw another tube as heretofore told. The switch 78 of the floor controller was closed duringthe pulling operacontroller F in operating during the return operation opens its switch 7 6 at a predetermined point, which results in the opening of the circuit to the reversing switch R as it follows through switch 76, the generator ceasing to generate a current to the motor, which stops as a result. The magnet 52 has closed its contacts 53 due to a lack of current also. Its contacts when closed bridge the switch 7 6 of the floor controller as told before, which results in restoring the circuit to the reversing switch R allowing the generator to again deliver a current to themotor, which in turn effects further return of the drawing mechanism 14 to the die, until finally stopped through the opening of switch 78 of the floor controller, through its further operation in the further return of the draw mechanism 14 to'the die 18.

To the switch E is fastened a catch 255, which holds the switch E in an inoperative position when not operating the draw bench. A brake B is provided for stopping the motor 12, being operated by the reversing switch R and B. When operating the reversing switch R, the circuit for current to operate the brake is had from junction point 119, by wire 125, contact 126 of reversing switch R, by wire 127 contact 128 of reversing switch R, segment 129, contacts 259, up to which point when operating reversing switch R, the circuit for current to operate the brake is from junction point 119, by wire 125, contact 126, segment 260, contact 261, by wire 262, contact 259, from which point in the case of either reversing switch bein operated, the circuit is, by wire 263, 0011 264 of brake R, by wire 265, junction point 180, by wire 181, junction point 182, by wire 183, when reversing switch R is operated, contact 184, segment 155, contact 156, by wire 157, junction point 158, by wire 159, to the minus main and when operating reversing switch R, the circuit is from the junction point 182, by wire 266, contact 267, segment 268, contact 269, by wire 270, junction point 158, by wire 159, to the minus main.

Having thus described my invention, What I desire to secure by Letters Patent of the United States is:

1. In a draw bench having a die for drawing metal tubing, the combination of the drawing mechanism, an electric motor to actuate the drawing mechanism to draw a tube and return the drawing mechanism to the die, and resistance, ada ted to be inserted in the circuit of the fie d winding of the motor, whereby the speed of the drawing mechanism 1n returning to the die is higher than its speed in drawing a tube.

2. In a draw bench for drawing metal tubing, the combination of the tube drawing mechanism, an electric motor to actuate it, and resistance, adapted to be inserted in tor, and automatic means so to insert the said resistance in the return movement of the drawing mechanism.

3. In a draw bench for drawing metal tubing, the combination of the tube drawing mechanism, an electric motor to actuate it, means adapted to cause the motor to operate at a higher 5 eed in the return movement of the drawing mechanism than in its operation of drawing a tube, the said means being automatically operable after the operation of reversing the movement of the drawing mechanism after the operation of drawing a tube.

4. In a draw bench for drawing metal tubing, the combination of the tube draw ing mechanism, an electric motor to actuate it, resistance adapted to be automatically inserted in the field of the motor, in the return movement of the drawing mechanism, and a generator to control the motor.

5. In a draw bench for drawing metal tubing, the .combination of the tube drawing mechanism, an electric motor to actuate it, and mechanism adapted to cause the motor to operate at a higher speed in the return movement of the drawing mechanism than in its operation of drawing a tube, said means comprising a resistance, adapted to weaken the field of the motor, and a switch adapted to insert the resistance, and automatically operable means to operate the switch.

6. In a draw bench for drawing 'metal tubing, the combination of the tube drawing mechanism, an electric motor to actuate it, and mechanism adapted to cause the motor to operate at a higher speed in the return movement of the drawing mechanism than in its operation of drawing a tube, said means comprising a resistance adapted to weaken the field of the motor, a weight and dash-pot operable switch adapted to insert the resistance'in the field.

7. In a draw bench for drawing metal tubing, the combination of the tube drawing mechanism, an electric motor to actuate it, and mechanism adapted to cause the motor to operate at a higher speed in its return movement of the drawing mechanism than in its operation of drawing a tube, said means comprising a resistance, adapted to weaken the field of the motor, a controlling switch for the motor, adapted to eflect the insertion of the resistance, and a weight adapted to operate the switch to close it to efiect the insertion of the resistance, and a dash-pot to control the time constant of the operation of the closing movement of the switch.

8. In a draw bench for drawing metal tubing, the combination of the tube drawing mechanism, an electric motor to actuate it to return the drawing mechanism to its initial position to draw a tube, controlling mechanism to control the motor in its operation of returning the drawing mechanism, said controllin mechanism comprising a switch, adapts to be operated automatically to efiect the reversal of the motor, to return the drawing mechanism.

9. In a draw bench for drawing metal tubing, thecombination of the tube drawing mechanism, an electric motor to return the drawing mechanism after it has drawn a tube to a position to draw another tube, and controlling mechanism to control the motor, comprising a switch, adapted to be operated automatically by a weight to effect the reversal of the motor to return the drawing mechanism. v i

10. In an apparatus for drawing metal tubing, comprising a drawing mechanism, to draw a tube, an electric motor to actuate the drawing mechanism, means to control the motor, comprising a switch, automatically operable to reverse the motor, and. means adapted to prevent the switch from operating automatically to reverse the motor at a given period.

11. In an apparatus for drawin metal tubing, comprising a drawing mechanism, to draw a tube, an electric motor to actuate the drawing mechanism, means to control the motor comprising a switch, automatically operable to reverse the motor, and means adapted to prevent the switch from operating automatically to reverse the motor at a given period during the operation of the motor in the drawing of a tube.

12. In an apparatus for drawing metal tubing, comprising a drawing mechanism to draw a tube, an electric motor to actuate the drawing mechanism, means to control the motor, comprising a switch, automatically operable to reverse the motor, and means adapted to prevent the switch from operating automatically to reverse the motor until the completion of the operation of the drawing mechanism in its operation of drawing the tube.

13. In an apparatus for drawing metal tubing, the combination of the drawing mechanism an electric motor for actuating it, controlling mechanism for the motor, comprising a switch, automatically operable to reverse the motor and return the drawing mechanism, and a magnet, adapted to prevent the switch from operating auto atiwhy to reverse the motor when the s w itch is in a given operated condition.

14. In a draw bench for metal tubing, comprising the drawing mechanism, an electric motor for actuating it, a switch to reverse the motor to return the drawing mechanism after it has drawn a tube, an electromagnet, adapted to hold the switch in its condition to operate the motor in the pull-' ing operation of the drawing mechanism, and means to deenergize the magnet upon the completion of the pulling operation of drawing the tube.

15. in a draw bench for metal tubing, comprising the drawing mechanism, an electric motor for actuating it, a switch to re-. verse the motor to return the drawing mechanism after it has drawn a tube, an electromagnet, adapted to hold the switch in its condition to operatethe motor in the pulling operation of the drawing mechanism, and means to deenergize the magnet upon the completion of the pulling operation of drawing the tube, comprising an electro-magnetically operable switch.

16. In a draw bench for metal tubing, comprising the drawing mechanism, an electric motor for actuating it, a switch to reverse the motor to return the drawing mechanism after it has drawn a tube, an electro-magnet, adapted to hold the switch in its condition to operate the motor in the pulling operation of the drawing mechanism, and means to deenergize the magnet upon the completion of the pulling operation of drawing the tube, comprising an electro-magnetmally operable switch, the electro-magnetically operable switch serving in operation to open the circuit to the electromagnet.

17. In a draw bench for metal tubing, comprising the drawing mechanism, an electric motor for actuating it, a switch to reverse the motor to return the drawing mechanism after it has drawn a tube, an electromagnet, adapted to hold the switch in its condition to operate the motor in the pulling operation of the drawing mechanism, and means to deenergize the magnet upon the completion of the pulling operation of drawing the tube, comprising an electro-magnetically operable switch, and automatic means to operate the released switch to reverse the motor to return the drawingmech anism to its position to draw another tube.

18. In a draw bench for metal tubing, comprising the drawing mechanism, an electric motor for actuating it, a switch to reverse the motor to return the drawing mechanism after it has drawn a tube, an electromagnet, adapted to hold the switch in its condition to operate the motor in the pulling operation of the drawing mechanism, an means to deenergize the magnet upon the completion of the pulling operation of drawing the tube, comprising an electro-magnetically operable switch, andautomatic means to operate the released switch to reverse thev motor to return the drawing mechanism to its position to draw another tube,

tubing, the combination of the drawing eration of the drawing mechanism returning from its position after drawing a tube to its position to draw a tube, the controlling mechanism comprising a switch automatically operable, adapted to eflect the interruption of the. current to the motor during the return travel of the drawing mechanism, whereby its speed is materially reduced, and an electro-magnetically operable switch, adapted thereupon to close to efiect a restoration of current to the motor whereby the drawing mechanism is caused to travel thereatger at low speed to its position to draw a tu e.

20. In a draw bench for drawing metal. tubing, the combination of the drawing mechanism, an electric motor to return the drawing mechanism from its position of drawing a tube to its position to draw a tube, a controlling mechanism to control the motor, comprising a switch automatically operable to interrupt the current to the motor during the return travel of the drawing mechanism, whereby'the speed of the drawing mechanism is materially slowed down, a switch automatically operable to close thereupon to restore current to the motor, whereby the drawing mechanism is caused thereafter to travel at low speed, and a switch automaticaliy operable to open to stop the motor when the drawing mechanism arrives at its position to draw a tube.

21. In a draw bench for drawing metai tubing, a drawing mechanism, an electric motor to actuate the drawing mechanism, means to prevent current from being admitted to the motor until it has stopped rotating, including an electro-magneticaily operable switch.

22. In a draw bench for drawin metal tubing, the combination of the rawing mechanism, an electric motor to actuate the drawing mechanism, a switch to reverse the motor, and an electro-magnetically operable switch, adapted to prevent the admission of current to the motor to operate it in a reverse direction until it has stopped, the magmotor,

net windings of the electro-magnetically operable switch being in a circuit from the current supply for the motor. 7

' 23. In a draw bench for drawing metal tubing, the combination of the drawing mechanism, an electric motor to actuate the drawing mechanism, a switch to reverse the motor, and an electro-magnetically operable switch, adapted to prevent the admission of current to the motor to operate it in a reverse direction until it has stopped, the magnet windings of the electro-magnetically operable switch being in a circuit from the current supply for the motor, the contacts of the switch being in a circuit to the reversing switch.

24. In a draw bench for drawing metal tubing, the drawing mechanism, an electric motor to actuate it, a generator for the motor, having a field winding, an electromagnetically operable overload switch, the winding of which is in the supply circuit for the motor, an electro-magnetically operable starting switch for the motor, the con-' tacts of the overload switch being in circuit with the starting switch, and the contacts of the starting switch being in circuit with the field winding of the generator.

25. In a draw bench for drawing metal tubing, the drawing mechanism, an electric motor to actuate it, a generator for the having a field winding, an electromagnetically operable overload switch, having two windings, one of which is in the supply circuit for the motor, and electromagnetically operable reversing switches for the motor, the other winding of the overload switch being in the circuit of the reversing switches, the contacts of the overload switch being in circuit with the reversing switches, and the contacts of the reversing switch being in circuit with the field winding of the generator.

In testimony whereof, I have signed my name to this specification.

DAVID C. LARSON. 

